Elucidating reaction mechanisms on quantum computers

We show how a quantum computer can be employed to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical-computer simulations for such problems, to significantly increase their accuracy and enable hitherto intractable simulations. Detailed resource estimates [...]

By | August 16th, 2017|Quantum Computing, QuArC (Redmond)|

APS Physical Review Letters selects Station Q paper on quasiparticle poisoning as Editors’ Suggestion

We are pleased to announce that the American Physical Society (APS) journal, Physical Review Letters, has selected the Station Q paper, Transport Signatures of Quasiparticle Poisoning in a Majorana Island, as an Editors’ Suggestion. The paper details how, working with theorists in Copenhagen, we found a way to measure the quasiparticle poisoning rate of a [...]

Magic state distillation with low space overhead and optimal asymptotic input count

In our quest for topological quantum computing with Majorana zero modes, one missing piece is the efficient, high-quality creation of magic states to perform the π/8 (or “T” gate). Our new paper, Magic State Distillation with Low Space Overhead and Optimal Asymptotic Input Count, provides a family of solutions to this need, allowing for a wide range [...]

By | March 27th, 2017|LIQUi|>, Quantum Computing, QuArC (Redmond), Software|

Solving the quantum many-body problem with artificial neural networks

Working together, ETH Zurich and Microsoft QuArC researchers have provided the first application of machine-learning techniques to solve outstanding problems in quantum physics. The neural networks used in their study developed a genuine intuition of the bizarre behavior of quantum particles. For example, after the artificial intelligence is trained on the elementary rules of quantum [...]

By | February 15th, 2017|Condensed Matter Physics, ETH Zurich, QuArC (Redmond)|

Design automation and design space exploration for quantum computers

A major hurdle for quantum algorithms for linear systems of equations, and for quantum simulation algorithms, is the difficulty to find simple circuits for arithmetic. Prior approaches typically led to a large overhead in terms of quantum memory, required operations, or implementation error. By leveraging recent advances in reversible logic synthesis, Martin Roetteler and Nathan [...]

By | January 25th, 2017|LIQUi|>, Quantum Computing, Quantum Simulation, QuArC (Redmond), Software|

Common framework for scientific experiments: QCoDeS

QCoDeS is an open source data acquisition framework that was created by distilling the homegrown solutions used in Station Q's experimental labs, and infused with all the best practices from the open source software world. It includes a simple syntax to define complex sweeps over n-dimensional parameter space, all the machinery required to visualize and [...]

By | January 3rd, 2017|Lab Automation, Quantum Computing, Software|

Transport signatures of quasiparticle poisoning in a Majorana island

As its name implies, the poisoning of Majorana devices by normal electrons is fatal to topological computation, so much effort is now focused on characterizing the degree of poisoning either by the creation of quasiparticle pairs within the device, or by electrons entering the device through the leads. A recent experiment (see https://arxiv.org/abs/1612.05748), led by [...]

A clear view of emerging and hybridizing Majorana zero modes using epitaxial InAs-Al nanowires

The first signature of Majorana physics, identified experimentally at TU Delft in 2012, focused on a characteristic conductance peak at zero voltage. It bore many signatures of Majorana zero modes, but had a sizable background signal that obscured how the peak arose out of coalescing Andreev bound states. Recently, Mingtang Deng and a Station Q [...]

By | December 27th, 2016|Condensed Matter Physics, Copenhagen – NBI, Majorana, Topological Phases|

Normal, superconducting and topological regimes of hybrid double quantum dots

Majorana devices will generally be much more complicated than the single-junction or single quantum dot Majorana devices that have been realized in the literature so far. (See https://arxiv.org/abs/1610.05289 by the Station Q team for examples of complex devices.) Recently, a first step toward complex multi-gated Majorana devices—a Majorana double quantum wire—was realized by Daniel Sherman and Jeremy [...]

By | November 23rd, 2016|Copenhagen – NBI, Majorana, Mesoscale and Nanoscale Physics|

Anomalous Fraunhofer Interference in Epitaxial Superconductor-Semiconductor Josephson Junctions

Last year saw a materials breakthrough, with the realization of a two-dimensional heterostructure combining superconductor and semiconductor layers. (See journals.aps.org/prb/abstract/10.1103/PhysRevB.93.15540.) Now, as shown in a recent report, this material has been used to study interference effects controlled by magnetic fields in a Josephson junction made from this material. Anomalous interference reveals properties of the semiconductor [...]

By | November 7th, 2016|Copenhagen – NBI, Material Science, Mesoscale and Nanoscale Physics|
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